The Effects of Inflammatory Tooth Pain on Anxiety in Adult Male Rats

Abstract

Introduction:This study aimed to examine the effects of induced inflammatory tooth pain on anxiety level in adult male rats.Methods:The mandibular incisors of 56 adult male rats were cut off and prefabricated crowns were fixed on the teeth. Formalin and capsaicin were injected intradentally to induce inflammatory tooth pain. Diazepam treated group received diazepam 30 minutes before intradental injection. The anxiety-related behavior was evaluated with elevated plus maze test.Results:Intradental application of chemical noxious stimuli, capsaicin and formalin, significantly affected nociceptive behaviors (P<0.001). Capsaicin (P<0.001) and formalin (P<0.01) significantly increased the anxiety levels in rats by decrease in the duration of time spent in open arm and increase in the duration of time spent in closed arm. Rats that received capsaicin made fewer open arm entries compared to the control animals (P<0.05). Capsaicin (P<0.001) and formalin (P<0.01) treated rats showed more stretch attend postures compared to the control and sham operated animals. In diazepampretreated rats, capsaicin induced algesic effect was prevented (P<0.001).Conclusion:Inflammatory pulpal pain has anxiogenic effect on rats, whereas diazepam premedication showed both anxiolytic and pain reducing effects.

Intra-periaqueductal gray matter administration of orexin-A exaggerates pulpitis-induced anxiogenic responses and c-fos expression mainly through the interaction with orexin 1 and cannabinoid 1 receptors in rats

“…These behaviors might increase the possibility of anxiogenic responses. In particular, previous studies showed anxiety-like behaviors following oral and intradental administrations of capsaicin in rats (Choi et al, 2013;Raoof et al, 2016). In addition, oral capsaicin exposure increased c-fos expression in the nucleus tractus of solitarius and paraventricular hypothalamic nucleus that are involved in the affective components as well as modulation of nociceptive signals (Choi et al, 2013;Condés-Lara et al, 2015;Hsu et al, 2014;Venkatraman et al, 2017).…”

“…Besides sensory features, it often produces considerable neurological problems such as sleep disruption, mental deficiencies and increasing vulnerability to emotional and anxiety disorders (Armfield and Heaton, 2013;Lavigne and Sessle, 2016;Raoof et al, 2015). In particular, a positive correlation has been observed between odontalgia and anxiety responses in both clinical and preclinical trials (Armfield and Heaton, 2013;Newton and Buck, 2000;Raoof et al, 2016).…”

Research Paper: The Modulatory Role of Orexin 1 Receptor in CA1 on Orofacial Pain-induced Learning and Memory Deficits in Rats

“…Conversely, in rats pretreated with a selective OX1R antagonist SB-334867-A, learning, and memory efficiency were worse than those of the capsaicin treated rats. Pain-related cognitive dysfunction is examined in numerous rodent models of pain ( Apkarian et al, 2004 ; Biessels et al, 1996 ; Cain, Francis, Plone, Emerich, & Lindner, 1997 ; Leite-Almeida et al, 2009 ; Raoof et al, 2016 ). Particularly, orofacial pain related learning, and memory dysfunction are recently noted.…”